This invention concerns a lead frame and a semiconductor device using the same and, more particularly, it relates to a technic useful for applying to a resin encapsulation lead frame and a resin encapsulated type semiconductor device.
Generally, a resin encapsulated type semiconductor device is manufactured by the process of bonding a semiconductor pellet on the tab portion of a lead frame, making an electrical connection between the electrodes of the semiconductor pellet and the inner leads of the lead frame, then forming a package made of a resin such as an epoxy resin by means of molding and then applying the cutting of the frame portion and the forming of the leads to the lead frame.
By the way, as the size for the semiconductor pellet has been increased in recent years, that for the tabs as the mounting portion therefor has also been increased correspondingly. While on the other hand, the size for the package for encapsulating the semiconductor pellet for the like is standarized. Accordingly, the length of a tab suspending lead embedded in the resin of the package is shortened and corrosive substances such as water are more liable to intrude along the interface between the tab suspending lead and the packing resin. Particularly, since moisture content or the like is more liable to intrude of defoliation occurs at the interface, it is desirable to provide a structure not causing the defoliation at the interface.
In view of the above, the present invention have made a study on forming a lock portion such as through holes at a portion of the tab suspending lead in order to enhance the bonding between the tab suspending lead and the encapsulating resin. In this way, defoliation at the interface between the lead frame and the packaging resin can effectively be prevented irrespective of the stresses formed upon cutting the tab suspending lead after the completion of the resin mold, or of the shear stresses resulting between them by the difference in the heat expansion coefficients between the lead and the packaging resin.